Our purpose is to study such immunologic adaptations by using a battery of six in vitro immune parameters to yield a composite immunologic profile. The study will be prospective and include both pre and post operative testing of cellular and humoral factors influencing the eventual clinical course of the allograft recipient. The following in vitro parameters will be assessed in all renal allograft recipients: 1) allogeneic stimulation (MLC), 2) mitogen stimulation, 3) the role and characterization of patient plasma factors effecting 1,24) cell mediated immunity (ADCC), 5) chemotactic response of PMN's and monocytes, 6) quantitation and functional interrelations of circulating lymphocyte subpopulations, i.e. T, B and null cells. It should be emphasized that the above data will be obtained prospectively, performed on a large number of patients, and be accompanied by detailed clinical correlations. It is our hope that the data obtained will a) better define preoperative biologic compatibiltiy of various donor-recipient pairs, b) have post-operative predictive, clinical value ultimately leading to improved and more appropriate diagnosis and management of clinical rejection and/or infection, and c) lead to a more sensitive titration of currently available immunosuppressive therapy.